Hitherto, some products are known, making use of the characteristic that neodymium compounds absorb light selectively in the vicinity of the wavelength of 580 nm. For example, first publication Sho 58-225148 discloses a selective light absorptive resin compound where neodymium oxide powder is dispersed in a transparent plastic base material, such as methacrylic resin, and optical products making use thereof. Furthermore, first publication Sho 60-161458 discloses neodymium-containing transparent resin compounds obtained by polymerizing a mixture of monomers such as alkyl (meth)acrylate and styrene, neodymium compounds such as neodymium acrylate, a carboxylic acid as a solvent of this neodymium compound and a polymerization initiator by the cell-cast method and optical products making use thereof.
These optical products have the characteristic of selectively absorbing light in the range of a wavelength of 580 nm, and are used in filters of color display equipment, such as color CRT, screen boards, lenses and lighting equipment.
However, the resin composition where neodymium oxide powder is dispersed in the transparent plastic base material is a disperse system of inorganic powder and therefore, there are the weak points that the transparency and light transmittance decreases, the absorption peak broadens, and further the quantity of absorbed light is small.
Since the optical products stated in first publication Sho 61-161458 are derived from a resin composition which is obtained by molecular binding a neodymium compound with, or dissolving it in a solvent and a polymer, there are changes in such properties as the mechanical characteristics of the polymer itself, and when trying to introduce a sufficient amount of neodymium compound, it brings about the inconvenience of grave deterioration of the mechanical and thermal properties of optical resin compounds and optical products.